Verify the identity.
cot (x - π/2) = -tan x
show work

Which is the equation of an ellipse with directrices at x = ±4 and foci at (2, 0) and (−2, 0)?

If m 17 27 90 63 ** picture is attached

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling